A method and system for evaluating the pollution resistance of an insulator

Abstract

The application provides an insulator pollution resistance evaluation method and system, and belongs to the technical field of insulator monitoring of a power system.The method comprises the following steps: using a high-power halogen light source to pulse-irradiate the surface of an insulator; continuously monitoring the surface of the insulator by using a multispectral imaging device; calculating the water content decay rate according to the monitoring data obtained by the multispectral imaging device; grading and evaluating the pollution resistance of the surface of the insulator according to the calculated water content decay rate; and performing pseudo-color processing according to the evaluation result to obtain a visual result of the pollution resistance level of the surface of the insulator.The application can quickly obtain reflectivity data by continuously monitoring the surface of the insulator by using the multispectral imaging technology, and can obtain the water content decay rate by using an accurate calculation method, so that the accurate evaluation of the pollution resistance of the insulator can be realized.

Description

Technical Field

[0001] This invention relates to the field of monitoring technology for power system insulators, and in particular to a method and system for assessing the pollution resistance of insulators. Background Technology

[0002] In power systems, the pollution resistance level of insulators is crucial to their performance. Long-term environmental contamination of insulator surfaces leads to a decline in line lightning withstand capability and insulation levels. To effectively assess the pollution status of insulators, the International Conference on Large Electric Systems (CIGRE) recommends pollution detection methods such as the equivalent salt density method, the pollution layer conductivity method, the pollution flashover voltage gradient method, the pulse counting method, and the leakage current method. These traditional detection methods primarily use electrical parameters such as conductivity, voltage gradient, and leakage current as characteristic quantities to reflect the overall pollution status of insulators. However, they generally suffer from low efficiency, complex processes, and high costs, making it impossible to achieve accurate and efficient live-line detection of the pollution level of insulators on a large scale. Furthermore, traditional methods cannot reflect the distribution of pollution on the insulator surface, nor can they reflect the pollution resistance of the insulator surface through the pollution status.

[0003] In recent years, various optical imaging technologies have been applied to the detection of pollution conditions in line insulators. Among them, solar-blind ultraviolet discharge imaging and infrared thermography are representative, offering advantages such as non-contact measurement and online detection, and can effectively detect abnormal corona discharge and heating problems in external insulation. However, under normal atmospheric conditions, even severe pollution of insulators may not necessarily cause a significant increase in surface leakage current or surface electric field distortion. The conditions for insulator heating and abnormal corona discharge are lacking, therefore, infrared imaging and solar-blind ultraviolet imaging are not sensitive enough to detect insulator pollution. Furthermore, sparse spectral insulator pollution imaging is currently mainly used to improve the contrast of polluted areas or to perform spectral analysis of pollution components; there is no method for evaluating the surface pollution resistance of insulators.

[0004] "Detection of Insulator Pollution Moisture Content Based on Hyperspectral Technology," by Ma Huan, Guo Yujun, Zhang Xueqin, et al., describes a prior art technique that uses hyperspectral technology to obtain real-time spectral information on the pollution state of insulator surfaces, thereby quantitatively detecting the pollution moisture content. First, a hyperspectral imager is used to acquire spectra of moist, contaminated samples. Black-and-white correction and multivariate scattering correction are then used to preprocess the acquired spectral lines to remove noise, scattering, and other interference. Next, a continuous projection algorithm is used to reduce the dimensionality of the data and extract the characteristic bands of the spectral lines. Finally, backpropagation neural network prediction models are established for the full band and characteristic bands, respectively, with root mean square errors of 0.1101 and 0.0768, respectively. While this prior art technique uses hyperspectral technology and a BP neural network algorithm to detect the pollution moisture content of insulators, hyperspectral equipment requires static imaging, demanding high stability and long imaging time. For practical insulator pollution moisture content detection and calibration, the moisture content exhibits different dynamic variation characteristics under different atmospheric humidity levels, making it difficult to achieve dynamic imaging and evaluation using hyperspectral imaging technology via drones or handheld devices. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a method and system for evaluating the pollution resistance of insulators.

[0006] The present invention adopts the following technical solution.

[0007] The first aspect of the present invention provides a method for evaluating the surface contamination resistance of an insulator, comprising the following steps:

[0008] The surface of the insulator is pulsed with a high-power halogen light source.

[0009] Continuous monitoring of the insulator surface is achieved using multispectral imaging equipment;

[0010] The water content decay rate was calculated based on monitoring data obtained from multispectral imaging equipment. ;

[0011] Based on the calculated water content decay rate The surface contamination resistance of insulators is graded and evaluated.

[0012] Based on the evaluation results, pseudo-colorization processing is performed to obtain a visual result of the insulator surface contamination resistance level.

[0013] Optionally, the high-power halogen light source has a light pulse wavelength range of 900nm to 2.5μm, a peak power of not less than 1500W, and a total energy of not less than 15J within the irradiated area.

[0014] Optionally, the monitoring data obtained by the multispectral imaging device includes data over a period of time. The insulator surface obtained by continuous imaging within the characteristic wavelength Reflectivity .

[0015] Optionally, the water content decay rate The result is obtained through exponential fitting, and the specific fitting function has the following form:

[0016]

[0017] in, After irradiation by a halogen light source Moisture content at any given time This represents the water content at the initial moment after halogen light irradiation. To fit the time delay, Indicates time, This represents the rate of decrease in water content.

[0018] Optionally, the moisture content The calculation formula is:

[0019] ,

[0020] Where A is -0.7123; B The value is 2.889, where A and B are empirical parameters; This represents the relative spectral reflectance.

[0021] Optionally, the relative spectral reflectance For a specific wavelength reflectivity Reflectivity of standard gray board The root mean square of the ratio is calculated using the following formula:

[0022]

[0023] in, The number of units in the characteristic wavelength sequence. The characteristic wavelength is denoted as .

[0024] Optionally, the characteristic wavelength Including 458.5nm, 543.2nm, 671.5nm, 750.5nm, 915.3nm and 997.9nm.

[0025] Optionally, the evaluation criteria for the surface contamination resistance of the insulator are as follows:

[0026] when The stain resistance level is Grade I, indicating a poor stain resistance level.

[0027] when The stain resistance level is Grade II, indicating a significant decrease in stain resistance.

[0028] when The stain resistance level is Level III, indicating a slight decrease in stain resistance.

[0029] when The stain resistance level is IV, indicating that the stain resistance level is relatively good.

[0030] Optionally, for vulcanized silicone rubber composite insulators, ~ The possible values ​​include:

[0031] =3.5, =6, 9.5 =13;

[0032] For ceramic insulators ~ The possible values ​​include:

[0033] =2.5, =4.5, 7, =10.

[0034] A second aspect of the present invention provides a system for evaluating the surface contamination resistance of an insulator, based on the method for evaluating the surface contamination resistance of an insulator as described in the first aspect of the present invention. The system includes:

[0035] The system includes a high-power halogen light source, a multispectral imaging device, a moisture content attenuation rate calculation module, a grading and evaluation module, and a visualization module. The high-power halogen light source is used to pulse-irradiate the insulator surface, the multispectral imaging device is used for continuous monitoring of the insulator surface, the moisture content attenuation rate calculation module is used to calculate the moisture content attenuation rate based on the monitoring data, the grading and evaluation module is used to grade and evaluate the insulator surface's pollution resistance based on the moisture content attenuation rate, and the visualization module is used to perform pseudo-colorization processing based on the evaluation results and output a visualized result of the insulator surface's pollution resistance level.

[0036] Compared with the prior art, the beneficial effects of the present invention include at least the following: The present invention provides a method for evaluating the surface contamination resistance of insulators based on multispectral imaging technology, which has the following advantages compared with the prior art:

[0037] 1. High efficiency and accuracy: This invention uses multispectral imaging technology to continuously monitor the surface of insulators, which can quickly acquire reflectivity data and calculate the water content attenuation rate through precise calculation methods, thereby achieving an accurate assessment of the insulator's pollution resistance.

[0038] 2. Real-time dynamic monitoring: Unlike traditional static detection methods, this invention can achieve real-time dynamic monitoring of the insulator surface, providing more continuous and comprehensive data support.

[0039] 3. Visualized assessment: This invention uses pseudo-color processing to visually display the results of the stain resistance assessment, making the assessment results more intuitive and easier to understand, and facilitating quick decision-making by maintenance personnel.

[0040] 4. Easy to operate: This invention simplifies the operation process, reduces reliance on specialized equipment, makes the evaluation process easier, and lowers the skill requirements for professionals.

[0041] 5. Cost-effectiveness: Compared with traditional methods, this invention reduces equipment investment and labor costs, and improves the economic efficiency of the evaluation.

[0042] 6. Strong environmental adaptability: This invention is not limited by general atmospheric conditions. Even if it does not cause a significant increase in surface leakage current or distortion of surface electric field on the insulator surface, it can still sensitively reflect the pollution status of the insulator.

[0043] 7. Comprehensive evaluation: This invention not only evaluates the overall pollution status of insulators, but also reflects the surface pollution distribution characteristics, comprehensively evaluates the impact on flashover voltage, and provides a more comprehensive evaluation result. Attached Figure Description

[0044] Figure 1 This is a schematic diagram of the visualization results (RH=55%) of the stain resistance assessment and grading provided in accordance with the embodiments of the present invention;

[0045] Figure 2 This is a schematic diagram of the method flow provided according to an embodiment of the present invention. Detailed Implementation

[0046] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of this invention. The described embodiments are merely some embodiments of this invention, and not all embodiments. Based on the spirit of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this invention.

[0047] Previous research by the patent applicant has shown that the moisture content of contaminants on the insulator surface is closely related to its contamination resistance (such as hydrophobicity). When the hydrophobicity of the insulator surface decreases or powdering occurs, the drying ability of the contaminant layer under humid conditions also decreases significantly, and the dehydration rate under the same conditions is positively correlated with the hydrophobicity of the insulator surface. Therefore, this invention aims to use multispectral imaging technology to calculate the water content per unit area by analyzing the spectral reflectance of specific bands, and to assess the contamination resistance of the insulator surface by observing the change in water content after active heat source irradiation, thus achieving non-contact, continuous, and visualized dynamic monitoring. The reflectance spectral imaging technology can select several characteristic bands of the insulator to achieve wide-band sparse spectral imaging, fully leveraging the advantages of sparse spectral cameras—small size, fast imaging speed, and high image spatial resolution—without sacrificing the accuracy of contamination condition assessment.

[0048] This invention provides a method for continuously monitoring the surface moisture content of insulators through a combination of active heat source irradiation and multispectral imaging technology, and for evaluating their pollution resistance using an exponential model. This method uses the moisture content decay rate to visually grade and evaluate the pollution resistance of the insulator surface.

[0049] In Example 1, this invention provides a method for evaluating the surface contamination resistance of insulators, such as... Figure 2 As shown, the method includes the following steps:

[0050] Step 1: Pulse irradiation of the insulator surface using a high-power halogen light source;

[0051] In a further preferred but non-limiting embodiment, the high-power halogen light source has a light pulse wavelength range of 900nm to 2.5μm, a peak power of not less than 1500W, and a total energy of not less than 15J within the irradiated area;

[0052] Furthermore, an effective prerequisite for conducting irradiation and spectral image monitoring is that the relative humidity of the atmosphere is not lower than 40%.

[0053] Step 2: Continuously monitor the surface of the insulator using multispectral imaging equipment;

[0054] In a further preferred but non-limiting embodiment, the monitoring data includes:

[0055] The pixel grayscale matrix of the multispectral image obtained by a multispectral imaging device through continuous shooting of a fixed object over a period of time t can be converted into a pixel position reflectance matrix.

[0056] Step 3: Calculate the moisture content decay rate based on the monitoring data;

[0057] In a further preferred but non-limiting embodiment, the water content decay rate It was obtained through exponential fitting, and the specific fitting function is as follows:

[0058]

[0059] in, After irradiation by a halogen light source Moisture content at any given time This represents the water content at the initial moment after halogen light irradiation. To fit the time delay, Indicates time, It is the reciprocal of the time constant, i.e., the water content decay rate.

[0060] In a further preferred but non-limiting embodiment, the water content The calculation formula is:

[0061] ,

[0062] Where A is -0.7123; B The value is 2.889, where A and B are empirical parameters, and their values ​​are empirical values ​​determined by experiments and are preferred values ​​given in this invention. This refers to relative spectral reflectance. In a further preferred but non-limiting embodiment, the relative spectral reflectance... For a specific wavelength ( Reflectivity Reflectivity of standard gray board The root mean square of the ratio is calculated as follows:

[0063]

[0064] in, The number of units in the characteristic wavelength sequence. For the characteristic wavelength, preferably,

[0065] .

[0066] Step 4: Based on the moisture content attenuation rate calculated in Step 3, classify and evaluate the surface contamination resistance of the insulator;

[0067] In a further preferred but non-limiting embodiment, the insulator surface contamination resistance trace evaluation criterion is: when The stain resistance level is Grade I, indicating a poor stain resistance level.

[0068] when The stain resistance level is Grade II, indicating a significant decrease in stain resistance.

[0069] when The stain resistance level is Level III, indicating a slight decrease in stain resistance.

[0070] when The stain resistance level is IV, indicating a good level of stain resistance.

[0071] Among them, for vulcanized silicone rubber composite insulators and ceramic insulators, ~ The preferred values ​​are as follows:

[0072]

[0073] Step 5: Perform pseudo-colorization processing based on the evaluation results to obtain a visual result of the insulator surface contamination resistance level.

[0074] In a further preferred but non-limiting embodiment, step five specifically includes:

[0075] Based on the pollution resistance assessment results, characterization color levels are defined and pseudo-colorization processing is performed to obtain a visualization result of the pollution resistance level of the insulator surface.

[0076] For composite insulators, the hydrophobicity of the vulcanized silicone rubber surface decreases due to aging, and this decrease is reflected in the decay of the wettability of the contamination layer. Therefore, the evaluation of pollution resistance must consider both the feasibility of obtaining actual spectral images and the factor of the hydrophobicity (aging) of the contamination substrate. The pollution resistance assessment method provided by this invention combines active thermal light source and multispectral imaging to dynamically capture and calculate the wettability of the contamination layer, thereby obtaining the insulation pollution resistance level. This is a new approach and technological method.

[0077] In Example 2, based on the method described in Example 1, the following specific embodiment is provided:

[0078] 1. Equipment preparation and setup:

[0079] Prepare a high-power halogen light source, ensuring that its peak power of light pulse is not less than 1500W and the total energy within the irradiated area is not less than 15J.

[0080] Prepare a multispectral imaging device for continuous monitoring of changes in the reflectivity of the insulator surface.

[0081] 2. Pulse irradiation:

[0082] The surface of the slightly contaminated silicone rubber composite insulator sheet, which has undergone uneven corona aging, is subjected to pulse irradiation to ensure that the optical pulse meets the aforementioned power and energy requirements. At this time, the relative humidity of the atmosphere is 55%.

[0083] 3. Multispectral imaging monitoring:

[0084] Multispectral imaging equipment was used to continuously monitor the surface of the insulator and record the change in reflectivity of each pixel over time.

[0085] 4. Calculation of relative reflectivity:

[0086] Calculate the surface reflectivity of the insulator for a specific wavelength sequence (458.5, 543.2, 671.5, 750.5, 915.3, 997.9 nm). Reflectivity of standard gray board The relative reflectance is obtained as follows:

[0087]

[0088] by Taking a specific target area as an example, the calculation yields:

[0089] 5. Moisture content calculation:

[0090] by Taking a specific target area as an example, the calculation yields:

[0091]

[0092] 6. Fitting of water content decay rate:

[0093] Moisture content Over time The changes are as follows: Parameter fitting was performed, and the fitting result was... .

[0094] 7. Stain resistance rating assessment:

[0095] Based on the fitting The values ​​are used to grade and evaluate the surface contamination resistance of insulators. For vulcanized silicone rubber composite insulators, the corresponding areas... The area falls within the range of (0, 3.5], therefore the pollution tolerance level of this target area is Grade I, which is poor.

[0096] 8. Visualization Processing:

[0097] like Figure 1 As shown, based on the pollution resistance assessment results, characterization color levels are defined and pseudo-colorization processing is performed to obtain visualization results of the pollution resistance level of each region of the insulator.

[0098] In Example 3, the present invention provides an insulator pollution resistance assessment system, based on the insulator pollution resistance assessment method described in Example 1, the system comprising:

[0099] The system includes a high-power halogen light source, a multispectral imaging device, a moisture content attenuation rate calculation module, a grading and evaluation module, and a visualization module. The high-power halogen light source is used to pulse-irradiate the insulator surface, the multispectral imaging device is used for continuous monitoring of the insulator surface, the moisture content attenuation rate calculation module is used to calculate the moisture content attenuation rate based on the monitoring data, the grading and evaluation module is used to grade and evaluate the insulator surface's pollution resistance based on the moisture content attenuation rate, and the visualization module is used to perform pseudo-colorization processing based on the evaluation results and output a visualized result of the insulator surface's pollution resistance level.

[0100] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the specific implementation of the present invention. Any modifications or equivalent substitutions that do not depart from the spirit and scope of the present invention should be covered within the protection scope of the claims of the present invention.

Claims

1. A method for evaluating the surface contamination resistance of insulators, characterized in that, Includes the following steps: The surface of the insulator is pulsed with a high-power halogen light source; Continuous monitoring of the insulator surface is achieved using multispectral imaging equipment. The water content decay rate was calculated based on monitoring data obtained from multispectral imaging equipment. ; The monitoring data obtained by the multispectral imaging device includes a period of time. The insulator surface obtained by continuous imaging within the characteristic wavelength Reflectivity ; The water content decay rate The fitting function, obtained through exponential fitting, is: in, After irradiation by a halogen light source Moisture content at any given time This represents the water content at the initial moment after halogen light irradiation. To fit the time delay, Indicates time, The water content decay rate; The moisture content The calculation formula is: ， Where A is -0.7123; B The value is 2.889, where A and B are empirical parameters; Relative spectral reflectance; The relative spectral reflectance For a specific wavelength reflectivity Reflectivity of standard gray board The root mean square of the ratio is calculated using the following formula: in, The number of units in the characteristic wavelength sequence. Characteristic wavelength; Based on the calculated water content decay rate The surface contamination resistance of insulators is graded and evaluated. Based on the evaluation results, pseudo-colorization processing is performed to obtain a visual result of the insulator surface contamination resistance level.

2. The method for evaluating the surface contamination resistance of an insulator according to claim 1, characterized in that: The high-power halogen light source has a light pulse wavelength range of 900nm to 2.5μm, a peak power of not less than 1500W, and a total energy of not less than 15J within the irradiated area.

3. The method for evaluating the surface contamination resistance of an insulator according to claim 1, characterized in that: The characteristic wavelength Including 458.5nm, 543.2nm, 671.5nm, 750.5nm, 915.3nm and 997.9nm.

4. The method for evaluating the surface contamination resistance of an insulator according to claim 1, characterized in that: The evaluation criteria for the surface contamination resistance of the insulator are as follows: when The stain resistance level is Grade I, indicating a poor stain resistance level. when The stain resistance level is Grade II, indicating a significant decrease in stain resistance. when The stain resistance level is Level III, indicating a slight decrease in stain resistance. when The stain resistance level is IV, indicating that the stain resistance level is relatively good.

5. The method for evaluating the surface contamination resistance of an insulator according to claim 4, characterized in that: For vulcanized silicone rubber composite insulators ~ The possible values ​​include: =3.5， =6， 9.5， =13； For ceramic insulators ~ The possible values ​​include: =2.5， =4.5， 7， =10。 6. A system for evaluating the surface contamination resistance of an insulator, based on the method for evaluating the surface contamination resistance of an insulator as described in any one of claims 1-5, characterized in that, The system includes: The system includes a high-power halogen light source, a multispectral imaging device, a moisture content attenuation rate calculation module, a grading and evaluation module, and a visualization module. The high-power halogen light source is used to pulse-irradiate the insulator surface, the multispectral imaging device is used for continuous monitoring of the insulator surface, the moisture content attenuation rate calculation module is used to calculate the moisture content attenuation rate based on the monitoring data, the grading and evaluation module is used to grade and evaluate the insulator surface's pollution resistance based on the moisture content attenuation rate, and the visualization module is used to perform pseudo-colorization processing based on the evaluation results and output a visualized result of the insulator surface's pollution resistance level.

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